1. Field of the Invention
This invention relates to a biochemical analysis apparatus and a method of controlling same, and more particularly to controlling a biochemical analysis apparatus in which a frameless dry chemical analysis film having a reagent layer containing a reagent whose optical density changes through a chemical reaction, a biochemical reaction, an immunoreaction or the like with a specific biochemical component contained in a sample liquid such as blood or urine is taken out from a cartridge, transferred to a sample liquid spotting position, applied with a sample liquid by spotting in the sample liquid spotting position, transferred to an incubator, inserted into the incubator and taken out from the incubator and at least one of these steps is effected with the film held by a suction means.
2. Description of the Prior Art
There has been put into practice a "dry-to-the-touch" chemical analysis film with which the content of a specific chemical component contained in a sample liquid, the activity thereof or the content of a solid component can be quantitatively analyzed by only spotting a droplet of the sample liquid on the film. One example of a dry chemical analysis film, there has been known an integrated multi-layered chemical analysis film (sometimes referred to as "multi-layered chemical analysis element") comprising a support sheet of organic polymer and at least one reagent layer which contains a reagent and is formed on the support sheet. A spreading layer is sometimes provided over the reagent layer. Further, a dry chemical analysis element which is formed of filter paper and has one or more layers has been proposed and partly put into practice.
When quantitatively analyzing the chemical components or the like contained in a sample liquid using such a dry chemical analysis film, a droplet of the sample liquid is typically spotted on the film (on the spreading layer when the film is provided with a spreading layer and on the reagent layer when the film is not provided with a spreading layer) and is held at a constant temperature for a predetermined time (incubation) in an incubator so that a coloring reaction occurs. The optical density of the color formed by the coloring reaction is then optically measured. That is, a wavelength is pre-selected according to the combination of the component to be analyzed and the reagent contained in the reagent layer of the film. Measuring light containing this wavelength is then projected onto the film and the optical density of the film is measured. Then the concentration or the activity of the component to be analyzed is determined on the basis of the optical density using a calibration curve which represents the relation between the concentration of the biochemical component and the optical density.
The integrated multi-layered chemical analysis film is generally in the form of a film chip of a predetermined shape, e.g., as square or rectangle. The film chip is sometimes provided with a frame of organic polymer and used in the form of a chemical analysis slide. The frame helps to flatten the film chip which is apt to curl or warp in a dry state, thereby facilitating automated handling of the chemical analysis film. However use of the chemical analysis slide is disadvantageous in that the chemical analysis slide is larger than the chemical analysis film chip by the size of the frame and accordingly parts of the biochemical analysis apparatus must be larger, which obstructs reduction in size of the biochemical analysis apparatus and at the same time results in reduction of the overall throughput capacity of the biochemical analysis apparatus. Thus, the use of the chemical analysis slides adds to the cost of measurement.
In a biochemical analysis apparatus we have proposed previously, the film chip is used without a frame (hereinafter referred to as "frameless chemical analysis film"). A plurality of the frameless chemical analysis films are loaded in a cartridge and the cartridge is loaded in a chemical analysis film supplier for a biochemical analysis apparatus. The frameless chemical analysis films are taken out from the cartridge in the supplier one by one by use of a suction pad as disclosed, for instance, in our patent applications such as Japanese Patent Application No. 5(1993)-177056 and U.S. Patent Application No. 08/273,131, now U.S. Pat. No. 5,534,224.
Since the frameless chemical analysis film is curled or warped into a roof tile-shape in the dry state, taking out the film by attracting it under a suction force by the suction pad as described above should be the best way of taking out the film from the cartridge without damaging the surface of the film.
In the biochemical analysis apparatus, the frameless chemical analysis film taken out from the cartridge is transferred to the spotting position and a sample liquid is spotted on the film. Thereafter the film is transferred to the incubator and inserted into a cell in the incubator. After a predetermined incubation, the optical density of the biochemical substance is measured, and the film is taken out from the cell and discarded in a predetermined discarding box. In many of these steps, a plurality of suction means, e.g., suction pads and horseshoe-like suction means, are used to hold the frameless chemical analysis film. The suction pads and the horseshoe-like suction means are disclosed in detail in the Japanese patent applications identified above and the like.
Since the suction means must surely hold the frameless chemical analysis film which is light in weight and small in thickness, it is necessary to constantly keep the suction force at an optimal level. However, the suction force can be easily changed by various causes, such as a clog in the suction pipe from dust, defects in the vacuum pump, valves, filters or the like, and/or cracking in the suction means etc.
Further, since many suction means are used in the biochemical analysis apparatus, it is difficult for the operator to constantly check the suction force of each suction means.